@ckb-cobuild/molecule

An opinionated molecule library which defines schema in code.

• API Docs
• NPM Package

Browser Compatibility

• TypedArray: Can I Use?
• DataView: Can I Use?
• BigInt: Can I Use?

Compare With @ckb-lumos/codec

The differences between @ckb-cobuild/molecule and @ckb-lumos/codec:

• Lumos is flexible on the parameter type of the pack function, this library is strict and provides parse, safeParse, around to do conversions.
• Lumos table codec fields are nullable, this library only allows null for option field.
• This library supports schema validation via parse and safeParse.
• This library supports exporting molecule schema to .mol file.

About the Interface

This library prefers better type inferring and checking to sipmle schema definition. There will be many type names repetitions because of the limitation of TypeScript.

Example

Coerce

import { mol } from "@ckb-cobuild/molecule";
const ByteCoerce = mol.byte.beforeParse((input: any) => Number(input));

Use Different JavaScript Value

import { mol } from "@ckb-cobuild/molecule";
const ByteOpt = mol.option("ByteOpt", mol.byte);
const BooleanOpt = ByteOpt.around({
  safeParse: (input: boolean | null) => mol.parseSuccess(input),
  willPack: (input: boolean | null) =>
    input !== null ? (input ? 1 : 0) : null,
  didUnpack: (value: number | null) => (value !== null ? value !== 0 : null),
});

Validation

const result = codec.safeParse({/*...*/});
expect(result.success).toBeFalsy();
if (!result.success) {
  const messages = result.error.collectMessages();
  expect(messages).toEqual([
    "//: Struct member parse failed",
    "//a: Expected integer from 0 to 255, found undefined",
    "//b: Array member parse failed",
    "//b/0: Expected object, found null",
    "//b/2: Struct member parse failed",
    "//b/2/b2: Array member parse failed",
    "//b/2/b2/1: Expected integer from 0 to 255, found -1",
  ]);
}

Export Schema

import { mol } from "@ckb-cobuild/molecule";
const ByteOpt = mol.option("ByteOpt", mol.byte);
const ByteOptOpt = mol.option("ByteOptOpt", ByteOpt);
export(Array.from(ByteOptOpt.exportSchema().values())).toEqual([
  "option ByteOpt (byte);",
  "option ByteOptOpt (ByteOpt);",
]);